SNL310

16-Bit LCD Controller

8. EXTENSION BUS

SNL310 totally provides 64 I/O pins, those I/O pins can be configured to be address,

data and control signal of extension bus except P2.0~P2.15 are the dedicated general

I/O pins. Table-1 shows the relation among P3.5~P3.15, P4.0~P4.15, P5.0~P5.7 and

I/O pins.

I/O Pin

Extension Bus

Descriptions

P3.10

E_R

RD signal for 6800 interface

P3.15

A[22]

Address pin of 16-bit mode memory accessing

P3.11~P3.14

CS3~CS0

Chip select pin

P4.0~P4.15

A[0..15]

Address bus

P5.0~P5.5

A[16..21]

Address bus

P5.6

WR/RD

Write signal

P5.7

RD/E

Read signal

P5.8~P5.15

D[0..7]

Data bus

Table-1

SNL310 provides four chip select pins for external devices, each chip select pin can be

connected to memory device or LCD driver. Besides, all the address, data and control

pins of extension bus are shared with general I/O pins. Normally, the default setting is

general I/O pins for extension bus. User just need to set the enable control bit of

extension bus then all the corresponding I/O pins will switch to be extension bus

automatically.

8.1 Extension Bus for External Memory Device

SNL310 provides two access modes for external memory device. One is 8-bit mode

and another one is 16-bit mode. User has to use 16-bit mode if executed user’s

program is from external memory. Most important of all, SNL310 only can execute

user’s program from the first external device. So user has to connect Mask ROM or

Flash which already burn-in user’s program to the “CS1”

A0

A21

A21

SNL310

A0

CE\

CS1

mask ROM/

Flash

A22

A0

A22

A22

SNL310

A0

CE\

CS1

mask ROM/

Flash

8-bit Mode of Extension Bus

16-bit Mode of Extension Bus

Figure-5

Ver: 1.7

May 2, 2003

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